A Cappella and the Creation of Rhythm 1

Working in a timbrally-uniform medium such as unaccompanied voices has deepened my appreciation over the years for the insights that Grosvenor Cooper and Leonard B. Meyer provided into how rhythm works.

To ruthlessly summarise their key ideas:

Our experience of rhythm results from the perceptual organisation of relatively accented and unaccented sounds into coherent patterns.

An accent is created by any ‘stimulus marked for consciousness’ – that is, a thing that makes us notice it.

Consequently, any and all elements of a musical texture can participate in the creation of accent (and, thereby, rhythm).

We are used to thinking of accents as performance elements – either dynamic accents (creating a contrast of volume – usually a sound louder than the surrounding ones) or agogic accents (drawing attention to a sound by momentarily delaying it). But Cooper & Meyer’s formulation helps us see that most of the accents a listener hears are in fact built into musical structures by the composer (and, in my context, the arranger).

Now the reason that working in a cappella textures has particularly made me think about this is because it is quite a pared down medium in terms of the kinds of contrast you can use to create accent, and therefore rhythmic structure. You don’t get to add a cymbal crash or a fanfare in the brass to make a moment stand out like you do with an orchestra; neither do you get the regular patterns of contrast from the drumkit that popular traditions use to build their metrical frameworks. Even solo piano music has much more capacity for contrast, with its wide range and varied textures.

Now at this point, I realise I have far more thoughts about this subject than will fit in a single post, so I have gone back and added that ‘1’ in the title. Looks like we’re in for another series. So I’ll focus in the rest of this post on the kinds of accents that are available to unaccompanied voices. In subsequent ones I’ll look at the specific challenges and opportunities these present in two different a cappella contexts: homophonic genres (barbershop and homophonic parts of post-barbershop groups such as the Hi-Los and the Four Freshmen), and melody+accompaniment genres (from doo-wop to contemporary a cappella).

So, what kind of ‘structural’ accents is the a cappella arranger working with?

First, there are the ones built into the original song. These include, on the small scale:

Melodic accents: notes arriving after wider intervals draw attention more than those reached by smaller intervals

Range: related to this, notes at the extremes of a song’s range draw more attention than those in the middle. Typically, a melody uses higher notes to create accents, while an accompaniment uses lower ones. (Think of Scott Joplin to test this generalisation)..

Consonance/dissonance: notes that crunch against the harmony draw more attention than those that resolve into it. Renaissance polyphony of course is the genre that demonstrates this most clearly.

If you think about it, these are often used in tandem. The hook line of Passing Strangers, for instance, starts with a note that is durationally the strongest in the phrase, the highest in the phrase, and is markedly dissonant – no mistaking where the accent is here!

On the wider scale, songs use repetition to organise these collections of accented and unaccented notes into perceivable patterns. Again, think of Passing Strangers: the opening tune’s three-note motif in a rising sequence is what defines the length of the bar. And repetition on a wider scale still is what creates our sense of form – indeed, one of the interesting things about Cooper & Meyer’s theory is the way it gets you thinking about large-scale musical processes as aspects of rhythm, as well as the local bits you might tap your foot to.

Second, there are the ones we create through the act of arranging. These include:

Harmony: well, arguably that is part of the song rather than the arrangement, but I’m putting it here because we don’t always use all the same harmonies as you’ll find in the original. In any case, chord changes are a primary means for defining metre (whence the concept of harmonic rhythm, and harmonic charge is a significant way to shape longer stretches of musical time. That is, you’ll often find (and we’ll often place) the most striking or energy-filled chords at both melodic and lyrical climax points.

Voicing: As I discussed back in the winter, voicing often works in tandem with harmonic charge. This is because tighter voicings carry more musical energy than wider voicings, so you’ll often want to use both at once to create harmonic accents in the same places.

Voice-leading: The principles of melodic accents discussed above also work for harmonising voices. So, if you want the voices to be heard as independent parts, they need to move around more and include some jumps, but if you want them to meld into a single harmonic sound, you need to minimise their movement. Leaps in the bass across barlines, though, are useful to support the sense of harmonic accent.

Texture: There will be somewhat different decisions to make about texture depending on the stylistic world you’re working in (see my next two posts on the subject for more details!), but the principle remains the same in either case. Changes in texture draw attention to themselves, and so create accents.

See what I mean? This is already quite long enough for one post, and I’m only just getting going on the subject. No wonder Cooper & Meyer wrote a whole book about it. I (probably) won’t do that, but I will return in future posts to some more concrete examples of how these ideas can help with the kinds of technical and artistic challenges close-harmony arranging faces.